1. Field of the Invention
This invention relates to vehicle hoisting and towing apparatus, and more specifically to such apparatus employing hydraulic means for positioning and operating the towing boom.
2. Description of the Prior Art
The most advanced vehicle hoisting and towing apparatus in use today commonly employ multiple hydraulic actuators and controls. Such actuators and controls are capable of positioning the towing boom in proximity to the vehicle to be serviced and are capable of raising the vehicle into service and towing positions.
U.S. Pat. Nos. 3,620,393 to Bubik, entitled "Vehicle Towing Assembly" and 3,908,842 to Place entitled "Tow Truck" are representative of such apparatus. In each instance hydraulic actuators are employed to position the end of a towing boom in proper aspect to the towed vehicle and are used to raise the towing sling into the operative position. The concepts disclosed are useful in their intended environments but have limited utility under adverse conditions of terrain and footing.
For example, in mountainous terrain where the vehicle to be serviced lies at the foot of a steep embankment, the ability of the towing mechanic to work the hoisting operation is limited to the confines of the rearwardly extending boom. Additionally, in soft footings such as beach sand or roadside gravel, the hoisting operations is limited by the range of lateral stability of the towing vehicle. Although most towing vehicles ae not called upon to perform in such adverse conditions, vehicles along the West Coast of the United States commonly work both rugged mountain and expansive beach environments. To fill a need for flexible and adaptable vehicles in this region, mechanics and engineers are continually in search of new concepts for expanding hoisting capabilities while ensuring operator safety.